High Seebeck Coefficient Thermally Chargeable Supercapacitor with Synergistic Effect of Multichannel Ionogel Electrolyte and Ti_(3)C_(2)T_(x)MXene-Based Composite Electrode

Thermally chargeable supercapacitors can collect low-grade heat generated by the human body and convert it into electricity as a power supply unit for wearable electronics.However,the low Seebeck coefficient and heat-to-electricity conversion efficiency hinder further application.In this paper,we designed a high-performance thermally chargeable supercapacitor device composed of ZnMn_(2)O_(4)@Ti_(3)C_(2)T_(x)MXene composites(ZMO@Ti_(3)C_(2)T_(x)MXene)electrode and UIO-66 metal–organic framework doped multichannel polyvinylidene fluoridehexafluoro-propylene ionogel electrolyte,which realized the thermoelectric conversion and electrical energy storage at the same time.This thermally chargeable supercapacitor device exhibited a high Seebeck coefficient of 55.4 mV K^(−1),thermal voltage of 243 mV,and outstanding heat-to-electricity conversion efficiency of up to 6.48%at the temperature difference of 4.4 K.In addition,this device showed excellent charge–discharge cycling stability at high-temperature differences(3 K)and low-temperature differences(1 K),respectively.Connecting two thermally chargeable supercapacitor units in series,the generated output voltage of 500 mV further confirmed the stability of devices.When a single device was worn on the arm,a thermal voltage of 208.3 mV was obtained indicating the possibility of application in wearable electronics.

Boosting lithium batteries under harsh operating conditions by a resilient ionogel with liquid-like ionic conductivity

New chemistries are being developed to increase the capacity and power of rechargeable batteries. However, the risk of safety issues increases when high-energy batteries using highly active materials encounter harsh operating conditions. Here we report on the synthesis of a unique ionogel electrolyte for abuse-tolerant lithium batteries. A hierarchically architected silica/polymer scaffold is designed and fabricated through a facile soft chemistry route, which is competent to confine ionic liquids with superior uptake ability (92.4 wt%). The monolithic ionogel exhibits high conductivity and thermal/mechanical stability, featuring high-temperature elastic modulus and dendrite-free lithium cycling. The Li/LiFePO_(4) pouch cells achieve outstanding cyclability at different temperatures up to 150 ℃, and can sustain cutting, crumpling, and even coupled thermal–mechanical abuses. Moreover, the solid-state lithium batteries with LiNi_(0.60)Co_(0.20)Mn_(0.20)O_(2), LiNi_(0.80)Co_(0.15)Al_(0.05)O_(2), and Li_(1.2)Mn_(0.54)Ni_(0.13)Co_(0.13)O_(2) cathodes demonstrate excellent cycle performances at 60 ℃. These results indicate that the resilient and high-conductivity ionogel electrolyte is promising to realize high-performance lithium batteries with high energy density and safety.

Natural Rubber-Based Ionogels

Natural rubber(NR),besides being an abundant renewable resource for the elastomer industry,can be a potential resource for the design of innovative biobased polymer networks.The present work is based on“telechelic”liquid natural rubber oligomers obtained by controlled chemical degradation of NR.The chain ends of such oligomers can then be functionalized(with acrylate functions in the present case)and reacted with multifunctional crosslinkers in order to form networks.What’s more,the initial solubility of such thermosetting system in an ionic liquid(IL)can be used for the formulation of ionogels.Such solid networks typically containing 80%of IL were produced,resulting in high ionic conductivity performances.The oligomer chain length was shown to affect IL fragility due to confinement and specific interactions of ions with the host polymer network.

An interfacial robust and entire self-healing ionogel-elastomer hybrid for elastic electronics enables discretionary assembly and reconfiguration

Inspired by the multi-layer architecture of mammal skins,interfacial robust,stretchable,and entirely healable gel-elastomer hybrids hold great potential in diverse fields including biomedical devices,wearable electrical devices,and soft robotics.However,existing gel-elastomer hybrids have numerous limitations including low interfacial bonding toughness,complex and time-consuming preparation process,unhealable,and non-reconfiguration.Herein,we propose a simple and general chemical strategy through the interfacial dynamic bonding between gel and elastomer to simultaneously address the abovementioned obstacles.Dynamic covalent bonds readily and repeatably covalent bonding ionogel and elastomer(interfacial toughness:390 J m^(-2)),endowed the hybrids with entire self-healing features like skin and enabled discretionary assembly and reconfiguration.Moreover,this strategy resolved the troublesome contradiction between interfacial stability and reconfiguration.Taking advantage of the aforementioned features,we readily constructed a multi-module,self-healing,self-powered,and realtime monitoring of personal status integrated elastic electronics,which could simply reconfigure the output signal of elastic electronics into an input signal of the devices-braille keyboard.

Ionogels and eutectogels for stable and long-term EEG and EMG signal acquisition

Neurological injuries and disorders have a significant impact on individuals’quality of life,often resulting in motor and sensory loss.To assess motor performance and monitor neurological disorders,non-invasive techniques such as electroencephalography(EEG)and electromyography(EMG)are commonly used.Traditionally employed wet electrodes with conductive gels are limited by lengthy skin preparation time and allergic reactions.Although dry electrodes and hydrogel-based electrodes can mitigate these issues,their applicability for long-term monitoring is limited.Dry electrodes are susceptible to motion artifacts,whereas hydrogel-based electrodes face challenges related to water-induced instability.Recently,ionogels and eutectogels derived from ionic liquids and deep eutectic solvents have gained immense popularity due to their non-volatility,ionic conductivity,thermal stability,and tunability.Eutectogels,in particular,exhibit superior biocompatibility.These characteristics make them suitable alternatives for the development of safer,robust,and reliable EEG and EMG electrodes.However,research specifically focused on their application for EEG and EMG signal acquisition remains limited.This article explores the electrode requirements and material advancements in EEG and EMG sensing,with a focus on highlighting the benefits that ionogels and eutectogels offer over conventional materials.It sheds light on the current limitations of these materials and proposes areas for further improvement in this field.The potential of these gel-based materials to achieve a seamless interface for high-quality and long-term electrophysiological signal acquisition is emphasized.Leveraging the unique properties of ionogels and eutectogels holds promise for future advancements in EEG and EMG electrode materials,leading to improved monitoring systems and enhanced patient outcomes.

Photoelectric-driven conductive composite ionogel patch for effective wound healing

Developing the high biosafety,effective and wearable devices for fast wound healing is highly desired but remains a challenge.Here,we propose a“win–win co-operation”strategy to potentiate effective skin wound healing at the wound site by constructing robust and ecofriendly composite patch under opto-electric stimulation.The wearable patch is composed of ionic gel doped with Ti3C2Tx(MXene),which possesses good photothermal response to kill the bacteria via effective inhibition of the expression of inflammatory factors,preventing wound infection.Importantly,the composite ionogel patch is capable of providing green and on-demand electrical stimulation for wound site,guiding cell migration and proliferation by improved bioenergy and expression up-regulation of growth factor.In mice wound models,the treatment group healed~31%more rapidly.Mechanistically,the wearable devices could enable visual and real-time supervising treatment effect due to their good transmittance.The proposed strategy would be promising for future clinical treatment of wound healing.

Polymer ionogels and their application in flexible ionic devices

Polymer ionogel(PIG)is a new type of flexible,stretchable,and ion-conductive material,which generally consists of two components(polymer matrix materials and ionic liquids/deep eutectic solvents).More and more attention has been received owing to its excellent properties,such as nonvolatility,good ionic conductivity,excellent thermal stability,high electrochemical stability,and transparency.In this review,the latest research and developments of PIGs are comprehensively reviewed according to different polymer matrices.Particularly,the development of novel structural designs,preparation methods,basic properties,and their advantages are respectively summarized.Furthermore,the typical applications of PIGs in flexible ionic skin,flexible electrochromic devices,flexible actuators,and flexible power supplies are reviewed.The novel working mechanism,device structure design strategies,and the unique functions of the PIG-based flexible ionic devices are briefly introduced.Finally,the perspectives on the current challenges and future directions of PIGs and their application are discussed.

Durable and stretchable nanocomposite ionogels with high thermoelectric property for low-grade heat harvesting

Stretchable ionic thermoelectric(i-TE) materials have attracted growing interest in converting low-grade thermal energy into electricity. However, substantial improvement on i-TE performance of quasi-solid ionogels remains a significant challenge.Here, a nanocomposite ionogel with skin-like stretchability, high i-TE performance, thermostability and durability is prepared by hybridizing ionic liquid(IL) and Laponite nanosheets into waterborne polyurethane(WPU). With multiple H-bond, WPU can accommodate a higher content of IL, thereby improving its ionic conductivity. After cation exchange between IL and Laponite,the negatively charged Laponite sheets and released Na+can enhance the ionic Seebeck coefficient by enlarging thermophoretic mobility difference between the cations and anions in ionogel. Besides, incorporation of Laponite causes the decrease of thermal conductivity. Thus, the WPU-IL-Laponite ionogel exhibits a high ionic thermopower of 44.1 m V K-1, high ionic conductivity of 14.1 m S cm-1and low thermal conductivity of 0.43 W m-1K-1at a relative humidity of 90%. The corresponding ionic figure of merit of the ionogel is 1.90±0.27. Moreover, the ionogel demonstrates excellent durability during repeated stretching process.The stretchable ionogel can be fabricated into ionic thermoelectric capacitor to convert thermal energy from solar radiation into electricity.

Ultrastable Viologen Ionic Liquids-Based Ionogels for Visible Strain Sensor Integrated with Electrochromism,Electrofluorochromism,and Strain Sensing

Flexible electronics play a key role in the development of human society and our daily activities.Currently they are expected to revolutionize personal health management.However,it remains challenging to fabricate smart sensors with high robustness,reliability,and visible readout.Herein,high-performance electrochromic(EC),electro-fluorochromic(EFC),and double-network ionogels with excellent transmissivity,high mechanical robustness,and ultrastable reversibility are prepared by combination of thienoviologen-containing ionic liquids with poly(ethyl acrylate)elastomer.The ionogels exhibit good mechanical properties(1000%stretchability and 3.2 kJ m^(−2) fracture energy).The ionogel-based EC devices have a significantly simplified device fabrication process as well as superior cycling stability in which 88%of the contract ratio is maintained at 88%at 500 cycles,even after being stored for 2 years under ambient atmosphere(relative humidity:30%∼40%,25°C).The conductivity of ionogels showed a fast and reproducible response to strain,and the conductivity decreased with increased strain.By virtue of the EC and EFC properties of the thienoviologen component,the EC and EFC efficiency decreased with the increased strain loaded on the ionogels,and almost no EC or EFC phenomena were observed when the strain was above 300%.This feasible strategy provides an opportunity for the development of visible strain sensors to monitor the body’s movements through color and fluorescence emission.

Highly stretchable,conductive,and wide-operating temperature ionogel based wearable triboelectric nanogenerator

The rapid development of wearable electronic products brings challenges to corresponding power supplies.In this work,a thermally stable and stretchable ionogel-based triboelectric nanogenerator(SI-TENG)for biomechanical energy collection is proposed.The ionic conductivity of the ionogel increased to 0.53 S·m^(−1) through optimal regulation of the amount of aminoterminated hyperbranched polyamide(NH2-HBP),which also has high strain of 812%,excellent stretch recovery,and wide operating temperature range of−80 to 250°C.The SI-TENG with this ionogel as electrode and silicone rubber both as the triboelectric layer and encapsulation layer exhibits high temperature stability,stretchability,and washability.By adding appropriate amount of nano SiO2 to triboelectric layer,the output performance is further improved by 93%.Operating in singleelectrode mode at 1.5 Hz,the outputs of a SI-TENG with an area of 3 cm×3 cm are 247 V,11.7μA,78 nC,and 3.2 W·m^(−2),respectively.It was used as a self-charging power supply to charge a 22μF capacitor to 1.6 V in 167 s with the palm patting and then to power the electronic calculator.Furthermore,the SI-TENG can also be used as a self-powered motion sensor to detect the amplitude and frequency of finger bending,human swallowing,nodding,and shaking of the head motion changes through the analysis of the output voltage.

多糖基离子凝胶研究进展

离子凝胶在离子电导率和固液双相特性方面的独特优势而受到广泛关注.然而,采用人工合成聚合物所构筑的离子凝胶,存在着生物相容性差、生物可降解性不足、再生循环难度大、力学性能不足等问题,难以满足生态环境保护要求以及复杂应用场景需要.以天然多糖为主要原料构筑的多糖基离子凝胶,不仅具有良好的生物相容性和生物可降解性,多糖分子特殊的分子结构和丰富的官能团还可赋予离子凝胶独特的理化性质和优异性能,在众多领域显示出巨大的应用潜力.本文对近年来基于多糖(纤维素、海藻酸盐、壳聚糖、黄原胶和环糊精等)设计制备的离子凝胶及其应用进行了综述,并对其发展前景进行了展望.

可自修复海藻酸基离子凝胶的制备及性能

为了解决传统人工合成高分子基离子凝胶难降解、成本高、环境污染等问题,本文以天然高分子—海藻酸为聚合物基体,通过在离子液体中对其进行化学接枝改性和交联反应,设计并制备了一种具有自修复性能的化学交联型生物基离子凝胶。流变测试结果表明,该离子凝胶的模量随着海藻酸和交联剂含量的增加而升高,且在150℃的高温下离子凝胶依然可以保持凝胶结构。所制备的离子凝胶具有优异的压缩性能,压缩强度随着海藻酸含量的增加而增加,压缩强度可达1.02 MPa。电化学测试结果表明,离子凝胶具有良好的导电性能,其室温离子电导率都高于0.3 mS/cm。重要的是,离子凝胶在室温下无需任何辅助手段可在6 h完全自修复,表现出良好的自修复性。该研究为开发具有自修复性的高性能生物基离子凝胶提供了有效途径。

Highly Transparent,Stretchable,and Self‑Healable Ionogel for Multifunctional Sensors,Triboelectric Nanogenerator,and Wearable Fibrous Electronics

Ionogels with high transparency,stretchability and self-healing capability show great potential for wearable electronics.Here,a kind of highly transparent,stretchable and self-healable ionogels are designed using double physical cross-linking including hydrogen bonding and dipole–dipole interaction.Owing to the dynamic and reversible nature of the ion–dipole interaction and hydrogen bonds of polymeric chains,the ionogel possesses good self-healing capability.The multifunctional sensors for strain and temperature are fabricated based on ionogel.The ionogel can serve as strain sensor that exhibited high sensitivity[gauge factor(GF)=3.06]and durability(1000 cycles)to a wide range of strains(0–300%).Meanwhile,the ionogel shows rapid response to temperature,due to the temperature dependence of its ionic conductivity.Furthermore,the ionogel fbers with excellent antifreezing(−20°C)capability are fabricated,and the fbers show the good sensing performance to human motions and temperature.Importantly,the antifreezing ionogel-based triboelectric nanogenerator(ITENG)is assembled for efcient energy harvesting.The ITENG shows a short circuit current(ISC)of 6.1μA,open circuit voltage(VOC)of 115 V,and instantaneous peak power density of 334 mW m−2.This work provides a new strategy to design ionogels for the advancement of wearable electronics.

Transparent,stretchable,temperature-stable and self-healing ionogel-based triboelectric nanogenerator for biomechanical energy collection

A flexible and stable power supply is essential to the rapid development of wearable electronic devices.In this work,a transparent,flexible,temperature-stable and ionogel electrode-based self-healing triboelectric nanogenerator(IS-TENG)was developed.The ionogel with excellent stretchability(1,012%),high ionic conductivity(0.3 S·m^(−1))and high-temperature stability(temperature range of−77 to 250℃)was used as the electrode of the IS-TENG.The IS-TENG exhibited excellent transparency(92.1%)and stability.The output performance did not decrease when placed in a 60℃oven for 48 h.In addition,the IS-TENG behaved like a stable output in the range of−20 to 60℃.More importantly,the IS-TENG could also achieve self-healing of electrical performance at temperatures between−20 and 60℃and its output can be restored to its original state after healing.When the single-electrode IS-TENG with an area of 3 cm×3 cm was conducted under the working frequency of 1.5 Hz,the output values for open-circuit voltage,short-circuit current,short-circuit transferred charge,and maximum peak power density were 189 V,6.2μA,57 nC,and 2.17 W·m^(−2),respectively.The IS-TENG enables to harvest biomechanical energy,and drive electronic devices.Furthermore,the application of IS-TENGs as self-driven sensors for detecting human behavior was also demonstrated,showing good application prospects in the field of wearable power technology and self-driven sensing.

Organosilicon-group-derived silica-ionogel electrolyte for lithium ion batteries

In order to avoid leakage problem caused by liquid electrolyte, a new ionogel electrolyte was developed by in situ immobilizing organosilicon-functionalized ionic liquid within a nanoporous silica matrix. The ionic liquid evenly coats on the surface of porous silica and fills in the silica framework pores with no strong chemical interaction. The ionogel electrolyte has the dual advantages of a silica solid support and a wide electrochemical stability window of ionic liquid （4.87 V vs. Li^＋/Li）. The half-cells assembled with this electrolyte and LiFePO4 electrode have excellent performance at room temperature and 60 ℃. The Li/SiO2-IGE/LiFePO4 cell displays a discharge capacity of 129.1 mAh·g^-1 after 200 charge/discharge cycles at room temperature.

Finely Tuning the Lower Critical Solution Temperature of Ionogels by Regulating the Polarity of Polymer Networks and Ionic Liquids

Nonvolatile ionogels have recently emerged as promising soft electrolyte materials due to their high ionic conductivity and good durability.However,the compatibility between polymer networks and ionic liquids(ILs),which show significant influence on the physicochemical properties of the ionogels,has been rarely studied.Herein,we elucidate a lower critical solution temperature(LCST)-type phase behavior of ionogels composed of polyacrylates and hydrophobic 1-alkyl-3-methylimidazolium bis{(trifluoromethyl)sulfonyl}amide ILs.We systematically study the structural effects of ILs and monomers on the LCST of ionogels.Our work illustrates that the LCST of ionogels is primarily determined by the polarity of polymer side chains and the alkyl chain on cations of ILs.The oriented solvation between polymers and ILs caused by hydrogen-bonding effects and van der Waals interactions may serve as the driving force for the LCST phase behavior in our system.Furthermore,by varying the mixing ratio of two structurally similar ILs in their blends,the LCST of ionogels can be tuned to exhibit a linear variation within a wide temperature range(from subzero to over 200℃).Finally,thermoresponsive ionogels with desired patterns are prepared using photomasks.These nonvolatile ionogels with tunable LCST enriched the functionality of state-of-the-art ionogels,which provides insight into the design and fabrication of smart and flexible electronic/optical devices.

Ionogel-based flexible stress and strain sensors

Ionogels is a kind of hybrid materials composed of ionic liquids(ILs)and solid polymer network matrix,has been extensively investigated in the most recent decade.Due to the excellent mechanical properties and ionic conductivity,their promising applications in flexible stress and strain sensors have been proposed and explosively developed.In this review,we briefly summarize research progresses on ionogel based flexible stress and strain sensors(IFSSs)from five aspects,including material synthesis,device fabrication,working principles,characteristics and performances,and potential applications.Some outlooks and perspectives are also proposed at the end of review.The review is expected to provide reference and new insights into the research of IFSS.

双连续相增韧离子凝胶的制备及水下黏附性能

以2-丙烯酸-2-甲氧基乙酯(MEA)和2-(全氟辛基)乙基甲基丙烯酸酯(FMA)为共聚单体,在混合离子体系中通过自由基聚合诱导相分离方法,制备了一种由刚性液晶相和柔性渗透相组成的双连续相P(MEA-co-FMA)离子凝胶黏结剂,并对其力学性能和水下黏附性能进行了详细研究。通过调节FMA单体及离子液体(IL)的组分比,来调控聚合物网络的微相分离结构和可逆的非共价键作用,以实现对离子凝胶力学性能和水下黏附性能的同步提升。结果表明:该疏水双连续相结构离子凝胶具有高达24.2 kJ/m^(2)的断裂韧性和1.76 MPa的断裂强度,对不同基材的水下界面黏附韧性最高可达2260 J/m^(2),界面黏附的疲劳阈值可达558 J/m^(2),表现出了长效耐久的水下黏附性。

鳙鱼肽壳聚糖纳米颗粒的制备及体外性质研究

该研究通过离子凝胶法制备了负载鳙鱼肽的壳聚糖纳米颗粒。以包封率为主要指标,粒径、多分散性指数(polydispersity index,PDI)和Zeta电位值为参照指标,通过单因素试验筛选出最佳制备条件,并对包封前后多肽在模拟消化中的保留率进行了分析。结果表明,鳙鱼肽壳聚糖纳米颗粒最佳制备条件为:壳聚糖分子质量为50 kDa,壳聚糖溶液pH值为4,壳聚糖溶液质量浓度为0.5 mg/mL,壳聚糖与三聚磷酸钠质量比为6∶1。最佳条件下包封率为79.6%,粒径为212 nm,PDI值为0.411,Zeta电位值为+30.8 mV。傅里叶红外光谱表明,壳聚糖与三聚磷酸钠产生了交联,鳙鱼肽被包封在了壳聚糖纳米颗粒中。与未包封的肽相比,鳙鱼肽壳聚糖纳米颗粒热稳定性提高,并且提高了多肽在模拟消化过程中的保留率。该研究可为鳙鱼肽在食药生产中的应用提供一定的参考。

基于离子凝胶电解质的高稳定锌离子电池

锌离子电池因其安全性高和成本低而备受关注,然而严重的锌枝晶生长损害了电池性能的稳定性。在此,提出了将离子液体加入到聚(偏二氟乙烯-六氟丙烯)(PVDF-HFP)基体中制备离子凝胶电解质,离子液体的阳离子能吸附在锌尖端形成屏蔽层达到使Zn2+均匀沉积的目的。选用了咪唑类离子液体1-乙基-3-甲基咪唑三氟甲磺酸盐(EMIM(OTf))、1-丁基-3-甲基咪唑三氟甲磺酸盐(BMIM(OTf))和1-己基-3-甲基咪唑三氟甲磺酸盐(HMIM(OTf)),探究其阳离子侧链长度对锌枝晶生长的抑制效果。实验证明,由阳离子侧链长度适中的BMIM(OTf)制备出的离子凝胶电解质不仅具有1.87 mS/cm的高离子电导率,还能有效抑制锌枝晶生长,实现了2500 h锌金属负极的长循环稳定性,99.30%的高库伦效率,以及200次循环后全电池83.9%的容量保持率。该工作展示了离子液体凝胶聚合物电解质在高性能的锌离子电池领域的潜在应用价值。